- Hero Costume
- School Uniform
Seiji Shishikura (肉(しし)倉(くら)精(せい)児(じ) , Shishikura Seiji?) is a second-year student at Shiketsu High School.
Seiji Shishikura is a young man with small slanted black eyes and straight purple hair that covers his left eye. In his school uniform, Seiji wears the same white collared shirt and dark pants as all Shiketsu High students. He also sports Shiketsu's signature hat whether he be in uniform or in his hero costume.
Seiji's hero costume consists of a black overcoat with red trimmings. The collar covers Seiji's entire neck and is folded over. The sleeves of the coat are cut short and ended with a thick red cuff that is strapped to the upper part of the sleeve. His left sleeve also includes a smaller white cuff.
Seiji's overcoat reaches down past his knees and its torso doesn't have any designs other than red straps that appear to connect the two layers of the coat. He sports white, hard gloves that leave his index and pinky fingers exposed by connecting to the rest of his hands with red straps. Seiji completes his costume with black boots with red soles, a red mask, and Shiketsu's trademark hat.
Seiji in the manga. (Color ver.)
A sketch of Seiji as a civilian.
Seiji refusing to admit he's been influenced by Stain.
Seiji is a proud and dignified individual who takes values Shiketsu's teachings about obligation and dignity above all else. He often stands with his arms behind his back and uses eloquent language when speaking, which causes people to refer to him as "Sempai".
Seiji believes all heroes should be dignified and vulgar individuals are unworthy of becoming heroes. He believes this so strongly that he prioritized incapacitating unworthy students during the hero licensing exam over actually trying to pass the exam himself.
Seiji has a lot of respect for U.A. High but believes that the students of Class 1-A sully its image because they lack dignity. He dislikes Katsuki Bakugo especially and lectured him several times during their fight about how Katsuki needs to reflect on how he represents U.A. with his actions. He is also quite obviously insecure about his small eyes. When Katsuki teased him about it, he got angry and said his eyes were big and handsome.
Seiji considers himself to be worthy of being a hero and often fails to see his own faults and has trouble reflecting on his own actions. He has clearly been influenced by Stain to reform the hero position, but he refuses to admit being influenced by a villain. A Shiketsu teacher and Nagamasa Mora believe Seiji has a tendency of imposing his value on others and has been impacted negatively by the Hero Killer. This shortcoming is what ultimately caused Seiji to fail the hero licensing exam. Even so, Seiji remained mostly unphased and still refused to reflect on himself. 
Provisional Hero License Exam Arc
Shiketsu students start the first phase.
On the day of the Provisional Hero License Exam, Shiketsu High students arrive at Takoba National Stadium together. Fellow student Inasa Yoarashi notices U.A. students chanting "Plus Ultra" and crashes it. Seiji reprimands Inasa and tells him he shouldn't burst into other people's group. Inasa emphatically apologizes and Seiji tells him to leave with the others. 
The Shiketsu students change into their hero costumes and meet with the hundreds of other students inside the stadium for orientation. After Yokimiru Mera explains the rules, the first phase of the exam begins and the Shiketsu students split up. Seiji ends up in the city district of the arena and uses his Quirk to knead several students into balls of flesh. Katsuki, Eijiro, and Denki happen upon this area and Seiji attacks them immediately.
Seiji sends a mound of flesh at Katsuki but Eijiro jumps in the way and gets hit. Seiji transforms Eijiro into a ball of flesh and tells the other two U.A. students that his actions are simply a show of power. He says that Shiketsu students are obligated to wear their uniform hats while working as heroes because all of their actions are crowned in tradition. Seiji believes U.A. students like Katsuki lack this level of dignity and this makes his vulgar and ordinary.
"You're the worst of them Bakugo!"
Katsuki brushes off Seiji's monologue and insults his eyes, angering the Shiketsu student. Seiji says he has a lot of respect for U.A. but the students of Class 1-A ruin its dignity. Katsuki replies that Seiji needs to speak more with his actions rather than his words. Seiji is provoked into attacking and says that Katsuki is the perfect example of the aforementioned stain on U.A.'s reputation. Katsuki counters Seiji's flesh ball attacks with his AP Shot: Auto-Cannon Super Move and breaks the flesh apart with rapid-fire beams. 
Seiji laments allowing himself to get provoked and regroups after falling into Katsuki's trap. He calms down and decides to crush Katsuki's pride to force him to reflect on his actions. Katsuki rushes to attack and Seiji sends his flesh attacks at him. Katsuki blows them apart with his AP Shot attack and explosions. Denki shoots two orange disks at Seiji and he avoids them. He calls Denki an eyesore and threatens to turn him into a meatball.
Seiji shouts his superiority to Denki.
Katsuki demands Seiji not ignore him and attacks with another AP Shot. Seiji blocks it with a meat shield and says he hasn't been ignoring him. In fact, Seiji floated a mound of flesh beneath their elevated battlefield and used it to flank the U.A. students. A flesh attack lands on Katsuki's back and Seiji reminds him of what happened to Eijiro and calls checkmate. Katsuki is transformed into a ball of flesh and Seiji calls him pathetic.
Seiji reminds Denki that this is a show of power. He explains that he wishes to aid the examiners vetting process by eliminating unworthy heroes himself. Denki finds it odd that Seiji would prioritize this overpassing, but Seiji says it's odder for the number ordinary heroes to grow. Seiji reveals that people who have been turned into flesh balls retain their sentience. So if Denki uses his Electrification Quirk, he'll hurt his allies.
Denki tells Seiji he wishes he would stop spewing insults. Seiji replies that Denki has some self-awareness to his own flaws but Denki actually says he meant stop insulting his friends. Seiji attacks with his floating flesh but Denki counters by throwing a grenade at Seiji. Seiji barely dodges the explosion and is confused as to how something detonated with Katsuki immobilized. He quickly realizes that Katsuki gave Denki a grenade just before he was turned into a meatball.
Denki electrocutes Seiji.
Denki tells Seiji he stumbled into a great spot and then shoots electricity through him using his new Sharpshooting gear. Seiji happened to walk in front of the two disks Denki launched earlier and they act as conductors for Denki's electricity, allowing the electric current to pass through Seiji's body and severely injure him. Seiji falls on one knee and reals from the attack. He starts to lose his grip on the people he turned into meatballs and they slowly revert to normal.
Denki tells Seiji that his friends try hard to be heroes and that he has no right to judge them. Seiji gets angry and yells that he's trying to get them all to reflect on themselves. Katsuki and Eijiro return to their normal forms and attack. Eijiro punches Seiji in the gut and Katsuki finishes him off with an explosion. Seiji is incapacitated for the remainder of the first phase and fails the exam as a result. 
At the start of the second and final phase of the licensing exam, Seiji watches from the stands. He talks to what appears to be a Shiketsu teacher about Inasa's lack of experience and patience. The teacher says Seiji is the only Shiketsu student who has failed so far and he needs to reflect on himself. He fears Seiji's been too influenced by Stain to reform heroes. Seiji replies that its absurd that he would be influenced by a villain.
Remedial Course Arc
Seiji talks to his teacher about Camie's imposter.
Seiji accompanies Inasa and Camie to the end of the provisional license training course. Although he's not permitted to take part in the class, he's granted permission to observe. Shoto Todoroki and Katsuki are also present at the exam. Camie and Inasa talk to them but Seiji warns them not to sully themselves with sub-par students from U.A. High. Katsuki taunts him for failing the first phase of the licensing exam and Seiji gets angry with him. 
Before the training begins, Seiji sits with his teacher and says that Camie is a fool. The teacher argues that she's just bubbly and Seiji claims that's why the villains targeted her. Seiji is angry with himself for never noticing a member of the League of Villains impersonated his classmate.  The heroes in training are tasked with winning the hearts of troubled children from Masegaki Primary School. Seiji believes Inasa's warm personality is perfect for the task and he's clearly irritated when Inasa's first attempt fails. 
Seiji has a conversation with All Might.
Seiji joins Present Mic and commentates during the trial. He tells the hero students not to allow themselves to be provoked by the children. Seiji believes the students should not respond with force and they need to open a dialogue with the children. Present Mic questions how the children have such powerful Quirks and Seiji responds. He explains that Quirks that continue to mix from generation to generation will inevitably become stronger over time. There is a theory called the "Quirk Singularity" where some people believe Quirks will eventually run out of control.
Seiji is surprised when his peers use their Quirks to play with the children. He calls it a perfect parry to the kids' aggression and says they managed to deepen their interactions with the children without breaking their spirits. The four students pass the trial and exit the gymnasium. Outside they find Seiji talking to All Might. Camie comments on it and it makes him angry since they're talking about her. 
Seiji transforms Eijiro into a ball of flesh.
Overall Abilities: Seiji is a strong student, showcased by his position at Shiketsu High and his ability to fight on par with Katsuki, Eijiro, and Denki at the same time. Seiji has the respect of his fellow students, all of whom are students at the prestigious Shiketsu which is believed to be the best school in eastern Japan.
Seiji was able to outwit and overpower Katsuki and Eijiro before Denki rescued them and defeated several students before encountering them. It took the combined efforts of three U.A. students to bring Seiji down.
Meatball (精肉, Seiniku?): Seiji's Quirk gives him the ability to manipulate raw flesh, allowing him to manipulate other people's bodies by turning them into balls of flesh. He can also manipulate and detach his own flesh and remotely control it for offensive and defensive purposes.
Battles & Events
Provisional Hero License Exam Arc
Seiji and Inasa appear to have a calm and respectful relationship. Inasa looks up to Seiji and even refers to him as Sempai. Seiji has a good understanding of Inasa's personality and tries to keep him in check when he does something without dignity.
Seiji gets angry with Camie.
Seiji is easily annoyed by Camie's easygoing personality. He often yells at her angrily only to get an empty response from his classmate. She doesn't appear to listen to anything he says and this clearly annoys him. Even so, Seiji has displayed concern for Camie after a villain impersonated her.
Seiji and Katsuki cannot stand one another. They're basically polar opposites in regards to becoming heroes. Seiji believes Katsuki is vulgar and undeserving of becoming a hero. Katsuki constantly makes fun of Seiji's formal attitude by calling him Sempai. He also taunts Shishikura about his name and the size of his eyes. Even after the licensing exam, Seiji and Katsuki do not get along at all.
- Seiji's name contains the kanji for "flesh" (肉, shishi?), "storehouse" (倉, kura?), "refined" (精, sei?), and "child" (児, ji?).
- (To Katsuki Bakugo and Denki Kaminari) "I'll have to beat this lesson into you. Acting with class befitting one's institution... that is the meaning of dignity."
- ↑ 1.01.1 My Hero Academia Manga and Anime: Chapter 107 and Episode 56.
- ↑ 2.02.1 My Hero Academia Manga and Anime: Chapter 106 and Episode 55.
- ↑ 3.03.1 My Hero Academia Manga and Anime: Chapter 110 and Episode 57.
- ↑ My Hero Academia Manga and Anime: Chapter 102 and Episode 53.
- ↑ My Hero Academia Manga and Anime: Chapter 103 and Episode 53.
- ↑ My Hero Academia Manga: Chapter 163.
- ↑ My Hero Academia Manga: Chapter 164.
- ↑ My Hero Academia Manga: Chapter 165.
- ↑ My Hero Academia Manga: Chapter 166.
- ↑ My Hero Academia Manga: Chapter 167.
- ↑ My Hero Academia Manga: Chapter 107 (p. 2).